Production of lubricating oil



Patented May 27, 1952 UNETED STATES PATENT OFFICE PRODUCTION or LUBRICATING oiL Harold a. Stewart, Point Reyes statioa nd Wallace M. Thaw, San Pablo, Califi, assignors to California Research Corporation, San Francisco, Calif, a corporation of Delaware No Drawing. Application February 28, 1050, Serial N0. 146,910

3 Claims. (01. lee-"78) 1 Thi invention relates to hydrocarbon lubricating oils characterized by extremely high viscosity indices and to a process for the production of such oils from petroleum waxes.

The oils of this invention are produced by 5 chlorinating a petroleum wax and dehydrochlorinating the chlorinated Wax to produce a relatively saturated oil. The properties of the oil are Critically related to the degree of chlorination of the wax, and to the reaction v and catalyst employed in the dehydrochlorination' step. The oils are of complex chemical composition and cannot be defined in terms of the amounts of specific compounds of which they conditions are composed but must, rather, be defined l5 terms of the process by which they are produced,

In the past, it has been proposed to prepare lubricating oils from petroleum waxes by processes including steps of chlorination and dehydrochlorination. I posed taught dehydrochlorination under conditions such that a highly olefinic oil was produced; further, the processes proposed heretofore were so conducted that the inclusion of a The processes heretofore prodewaxing step was necessary where a product oil of low pour point was desired.

It is an object of this invention to produce from petroleum wax a lubricating oil characterized by a high viscosity index, and low bromine number by a process chlorinating the wax and dehydrochlorinating the chlorinated wax under conditions adapted to produce a saturated oil.

It is a further object of this invention to produce a substantially saturated lubricating oil characterized by a low pour point from petroleum wax by a process consisting only of the steps of chlorinating the wax and catalytically dehydrochlorinating the chlorinated wax.

comprising the steps of It has been found that valuable lubricating oils may be produced from petroleum wax by chlorinating the wax and then catalytically dehydrochlorinating the chlorinated wax in the presence of a silica-alumina catalyst at an elevated temperature above about 550 F. for a time sufiicient to produce a substantially saturated oil. It has further been found that a substantially saturated oil of low pour point may be produced in the process without recourse to a dewaxing step by chlorinating gr'ee such that the reaction mixture resulting from the chlorination step has a'chlorine content in the range 20-30% by weight.-

The chlorination step is conducted by lnelting the wax to a depetroleum wax and bubbling chlorine gas through the molten wax while agitating the liquid. If the chlorination is continued only until the reaction mixture has a chlorine content of 846%, for example; the mixture will contain substantial quantities of unrea'cted wax which come through the second step of the process unchanged and which impart a high pour point to the product oil. To illustrate, two samples of crude scale Wax chlorinated under identical conditions, one being chlorinated to a chlorine content of 8% by weight of. the reaction mixture and the other being chlorinated to a chlorine content of 20% by weight of the reaction mixture, were analyzed for their contents of unreacted wax. The sample which had been chlorinated to a chlorine content of 8% by weight showed an unreacted wax con,- tent of 39 weight per cent, while the sample which had been chlorinated to a chlorine content of 20% by weight showed an unreacted wax content of 3' weight per cent. Waxes of lower molecular weight, for example waxes having average molecular weights of about 350, should be chlorinated to a chlorine content of at least 25% by weight and preferably to 25-30% by weight in order to insure that substantially all of the wax molecules have acquired at least one chlorine atom. Waxes having a higher molecularweight, for example a molecular weight of 450-500 or higher, should be chlorinated to a chlorine content of at least 20% and preferably about 25% in order to insure substantially complete reaction of the wax with chlorine.- From the foregoing it willbe understood that when it is desired to produce a low pour point oil without the employment of a dewaxing step, a high degree of chlorination is necessary. I

The chlorination step is to be conducted at temperatures in the range of about 100.250 F. Temperature variations Within this range seem toafiect only the rapidity of the chlorination reaction and have no effect on the distribution of chlorinated products according to'chemical type.

Higher temperatures, for example 250 F. and

above, should be avoided in the chlorination step on total product.

3 above 550 F. but below that at which appreciable cracking is observed, preferably at a temperature in the range about 575-725 F.

The silica-alumina catalyst may be a synthetic silica-alumina catalyst such as those produced commercially for use in catalytic cracking, or it may be a natural silica-alumina clay such as a Florida clay, a montmorillonite clay, or it may be an acid treated natural clay such as that sold under the trade name of Filtrol clay.

The chlorinated wax and silica-alumina catalyst are maintained at dehydrochlorination temperature for a time sufficient to efiect substantially complete removal of the chlorine from the chlorine wax and to produce a substantially saturated oil. At about 600 F. a substantially saturated product is obtained with approximately /2 hour contact time. At higher temperatures the time may be shortened and is desirably shortened to approximately 10 minutes at 725 F. The times just noted have been found adequate in batch treatments of chlorinated wax with a silica-a1- lumina catalyst. It has been observed that if the dehydrochlorination step is conducted continuously that shorter contact times will sufilce. It is ordinarily preferred to treat the time element in the dehydrochlorination step as a dependent variable. When a catalyst of a particular activity has been selected and the amount of catalyst to be employed and the temperature of the dehydrochlorination treatment have been fixed, simple tests based on bromine number determinations will indicate the minimum satisfactory contact time.

Experiments have been conducted in which the amount of dehydrochlorination catalyst employed was varied while the other reaction conditions were held constant. These experiments indicate that at least 5 by weight of silica-alumina catalyst should be added to the chlorinated wax durin the dehydrochlorination step. The amount of silica-alumina ordinarily employed is in the range 13-13%. Larger amounts of catalyst have no adverse efiect on the dehydrochlorination but present the process problem of filtering and moving large masses of solid material.

The oil of this invention and the process by which it is produced are illustrated by the ,following examples:

Emample 1 Slack wax containing 21.2 oil was chlorinated to a chlorine content of 26.9% by weight, based The chlorinated stock was heated to 300 F. and by weight of Filtrol clay, such as that used for decolorizing petroleum lubricating oils, was added slowly. The mixture was heated continuously, with agitation to 550 F.

during a period of 90 minutes; the temperature of the mixture was held at 550 F. for 3 /2 hours. The dechlorinated mixture was cooled, filtered free from clay, neutralized, washed, solvent extracted from the water, and distilled to remove the solvent. An oil having the following characteristics was obtained:

Viscosity at 100 F., S. S. U 3367.9 Viscosity at 210 F., S. S. U 177.1 Viscosity index (Dean and Davis) 94 Pour point, "F 0 Molecular weight 480 Unsaturation mol, per cent 30 Remaining chlorine, weight per cent 0.54 Bromine No 10 4 Example 2 Slack wax containing 25.5% oil was chlo rinated to a chlorine content of 26.9% by weight. The chlorinated charge was mixed with 25% by weight of Filtrol clay, and the mixture was heated, with agitation, to 600 F. during a period of about 2 hours The temperature of the mixture was held at 600 F. for 30 minutes after which the dechlorinated mixture was cooled and filtered free from clay. A red oil with a green :bloom having the following characteristics was obtained.

Viscosity at 100 F., S. S. U 684.4

Example 3 A white refined paraifin wax having a low oil content and a molecular weight of 480-500 was chlorinated to a chlorine content of 20% by weight of the reaction mixture. The reaction product of the chlorination step was dehydrochlorinated both batchwise and continuously. The continuous dehydrochlorination reactor consisted of a slanted tube surrounded by a heating mantle. Chlorinated wax and clay were pumped in at the top and the clay remained in suspension due to the rapid flow through the reactor. The temperature of the reactor was held at slightly above 600 F. A thermocouple in the middle section of the reactor indicated that the feed had reached 600 F. by the time that it had reached this point. Reaction conditions and inspections of the oil obtained in these experiments are summarized in the following table:

Operation Batch Continuous Run WT-2-46 WT-ll1-14 Feed Stock:

Molecular Weight 470 470 Per Cent Oil by weight 0. 31 0.31 Melting Range, F 143-150 143'150 Viscosity at 210 F., SSU 42.1 42.1 Dehydrochlorination:

Heat-up Time 87 Minutes 5 to 10 Seconds Final Temperature, "F 600 Time at Final Temperature 30 Minutes 10 to 20 Seconds Per Cent Filtroi Clay 20 10 Inspections on Product:

Per Cent Chlorine by weight 0.03 0.22 Rarnshottom Carbon Percent 0. 30 0. 16 Conradson Carbon Per Cent 0.27 0.00 Molecular Weight 540 460 Bromine Number 4 32 M01 Per Cent Unsaturatiom- 13. 5 92. 0 Viscosity at 100 F., SSU 271. 5 131. 6 Viscosity at 210 F., SSU 54.8 44.1 Viscosity Index 125 141 Cleveland Flash Pt, F 440 430 P0111 Point, F 90 85 Gravity, API 31.2 20. 6 Yield (Weight Per Cent 01 Charge Wax) 82. 4 80. 0

Example 4 Per cent remaining chlorine 0.56 by weight Molecular weight 585 Pour point 15.

Flash point 455 F. Viscosity S. S. U. 100 F 1401.1 Viscosity S. S. U. 210 F. 110.7 Viscosity index 101 The temperature of 740 F. employed in this run I was somewhat above the preferred maximum of 725 F. and some cracking was observed. It should be noted that the pour point of the oil produced was low and that no dewaxing step was required to attain this pour point.

Example A distillation cut from slack wax containing 27.3% oil and having a molecular weight of 490 was chlorinated to 9.0% by weight based on reaction mixture. The chlorinated charge was mixed with by weight of Filtrol clay, and the mixture was heated, with agitation, to 640 F. during a period of about 2 hours. The temperature of the mixture was held at 640 F. for one hour after the dehydrochlorinated mixture was cooled and filtered free from clay. The stock was then dewaxed at -10 F. The dewaxing solvent was removed by distillation and the oil was vacuum distilled to 415 F. pct temperature at 2 mm. pressure. The following inspections were obtained on the oil:

Viscosity at 100 F., S. S. U 281.1 Viscosity at 210 F., S. S. U 53.4 Viscosity index i 114 Molecular weight 500 Bromine No 5 Flash point 460 Pour point "F 1 5 Conradson carbon percent 0.26 Percent chlorine by weight 0.14

The above Example 5 illustrates the production of an oil of low olefin content from a low value slack wax by chlorination to a low chlorine content, dehydrochlorinating at a temperature above 550 F. and dewaxing the oil produced in the dehydrochlorination step.

The foregoing description and examples set forth a method of producing a substantially saturated oil having a high viscosity index and a low pour point from petroleum wax. Various modifications of the process may be made by those skilled in the art without departing from the scope of the appended, claims.

We claim:

1. A process for producing lubricating oil from petroleum Wax which comprises the steps of chlorinating the wax to such a degree that the whole reaction product of the chlorination step has a chlorine content in excess of 20% by weight and catalyticaliy dehydrochlorinating said reaction product by contacting it with at least 5% by weight of a silica-alumina catalyst at a temperature in the range about 600 to 725 F. for a time suiiicient to substantially completely remove the chlorine from the chlorinated Wax and to produce a relatively saturated oil.

2. A process for producing lubricating oil from petroleum wax having an average molecular Weight in the range about 350 to about 9% which comprises the steps of chlorinating the Wax at a temperature below 250 F. to a degree such that the reaction product of the chlorination step has a chlorine content in the range 20-30% by Weight, the degree of chlorination being varied inversely with the molecular weight within their respective ranges, and catalytically dehydrochlorinating the reaction product of the chlorination step by contacting it with 13-13% by weight of a silica-alumina catalyst at a temperature in the range about 600 to 725 F. for a time suificient to substantially completely remove the chlorine from the chlorinated wax and to produce a relatively saturated oil.

3. A process for producing a lubricating oil of a lubricating oil of low olefin content from petroleum wax which comprises chlorinating the wax at a moderately elevated temperature below 300 F. to such a degree that the whole reaction product has a chlorine content in excess of 20% by weight, dehydrochlorinating the chlorinated wax by contacting it with at least 5 by weight of a silica-alumina catalyst at a temperature in the range about 600 to 725 F. for a time sufficient to substantially completely remove the chlorine from the chlorinated wax by dehydrochlorination and dewaxing the reaction product of the dehydrochlorination step.

HAROLD R. STEWART. WALLACE M. THAW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,094,593 Gardiner et a1 Oct. 5, 1937 2,401,636 Haensel et al June 4, 1946 

1. A PROCESS FOR PRODUCING LUBRICATING OIL FROM PETROLEUM WAX WHICH COMPRISES THE STEPS OF CHLORINATING THE WAX TO SUCH A DEGREE THAT THE WHOLE REACTION PRODUCT OF THE CHLORINATION STEP HAS A CHLORINE CONTENT IN EXCESS OF 20% BY WEIGHT AND CATALYTICALLY DEHYDROCHLORINATING SAID REACTION PRODUCT BY CONTACTING IT WITH AT LEAST 5% BY WEIGHT OF A SILICA-ALUMINA CATALYST AT A TEMPERATURE IN THE RANGE ABOUT 600* TO 725* F. FOR A TIME SUFFICIENT TO SUBSTANTIALLY COMPLETELY REMOVE THE CHLORINE FROM THE CHLORINATED WAX AND TO PRODUCE A RELATIVELY SATURATED OIL. 